Horizontal cracking to the external masonry of a property that is of cavity construction indicates a serious structural defect which will need to be investigated by a specialist.
In the most common instances short horizontal cracks within the mortar bed will indicate that the wall ties have failed and are suffering from oxidisation.
With a failure in the wall tie caused by corrosion iron oxide layers build up on the tie increasing the ties mass, lifting the brick which separates the brick from the mortar it was laid on to therefore the connection between the internal skin of masonry and the external skin of masonry is lost leaving the potential for collapse of the masonry which has happened.
If you have horizontal cracking to the external skin of masonry you should initially contact a wall tie specialist like ourselves and have an intrusive Wall Tie Survey carried out so that the cause of the cracking can be diagnosed and a suitable repair scheme implemented.
Wall Tie Replacement is a delicate process which although appears simple should not be deemed so. Many Wall Tie replacement contractors come and go usually due to poor workmanship and incompetence so always use a reputable company.
Newman’s are approved by the manufacturer Twistfix to design and install replacement Wall Tie schemes which we can guarantee for up-to 25 years. We specialise in Wall Tie Replacement and have designed and implemented many schemes.
Thermal movement is a fairly new cause of concern within the construction industry as the use of new modern materials are utilised within construction, the speed of which buildings are erected and the requirement for stronger materials that we can work faster with have been required in the industry as technology has advanced.
Thermal movement doesn’t pose serious threat to the structural integrity in the first instance but over time the damage caused can become very serious. Bricks and mortar are extremely strong and able to resist high compressive forces but offers very poor performance when subject to tensile forces.
Thermal movement is basically caused by the expansion and contraction of the fabric of the building due to hot and cold weather. When it’s hot the masonry expands causing compressive forces which the masonry can cope with due to its high compression strength but once it’s cold the material shrinks with tensile forces causing cracking. This cycle is repeated and small cracks eventually turn into large cracks.
Period properties rarely suffer from Thermal movement as many were constructed using soft lime mortars which allow movement slight movement usually accompanying thermal movement.
Modern structures are sometimes built without any expansion joints so the thermal movement cannot be accompanied within the masonry so cracking occurs.
Remedial measures are required in order to prevent further cracking and this should only be carried out by a specialist. Expansion joints are usually a 20mm wide cut which creates a separation in the masonry allowing each panel to accommodate the movement without cracking occurring.
Newman’s use the unique Twistfix system which incorporates specialist slip ties and the patented CD drivefix tie combined with a backing cord and flexible mastic creating an expansion joint.
We can guarantee all works for up to ten years and have carried out many projects requiring expansion joints to prevent further cracking.
Bulging walls in period properties are a common defect that are often seen along the gable and flank elevations of a property. This defect is especially common in Edwardian and Victorian properties but is also evident in properties of all ages.
Bowing walls should not be regarded as ‘just the way it was built’ this is a serious structural defect that will require a structural repair solution in order to prevent further movement or complete failure.
If the bowing in the wall is only at the levels where the floor joists run either into or alongside then this is more than likely to indicate that lateral movement also known as outward movement has occurred.
Lateral movement occurs when there is no connection between the masonry and the floor joists or stair case allowing the masonry to move independently. In order to prevent further outward movement you must provide a connection between the two.
Newman’s utilise Twistfix lateral restraint ties which are an 8mm stainless steel tie which are installed externally through a 12mm hole in the masonry into the floor joist. With a concealed resin fix to the masonry we are able to tie the masonry to the floor joist which restrains any further movement.
In modern properties or buildings constructed with a cavity wall then the bowing if not confined to the floor joist levels only could indicate that there are other structural defects such as wall tie failure which will need to be assessed.
Out lateral restraint schemes for bowing walls can be guaranteed for ten years covered by an IGL insurance backed guarantee. Contact us today if your property is showing signs of outward movement.